A chromatographic method for determining glycated hemoglobin (Hb A1c) by use of a new monodisperse cation-exchanger has been investigated. Hb A1c was separated from other "minor hemoglobins": Hb F, Hb A3 (the glutathione adduct), and the acetaldehyde adduct in alcoholics. The method was fully automated and a single column could be used for more than 1000 runs. The normal reference interval was ...

Measurement of hemoglobin A1c (Hb A1c) 2 is a fundamental component of the management of patients with diabetes mellitus. Hb A1c measurement provides an indication of chronic exposure to glucose and is extensively used for both monitoring long-term glycemic status and evaluating whether an individual patient has attained adequate metabolic control. The patient’s Hb A1c value is used by clinicia...

Hb F, some of which is glycated (2), accounts for the majority (70%–95%) of Hb species in newborns. About 5%– 30% is Hb A, with none to trace amounts of Hb A1c. This patient’s sample was collected after transfusion of 2 aliquots of red blood cells from a single donor. The donor’s blood contained 12.6% Hb A1c. Concentrated glucose in blood storage media increases donor Hb A1c only minimally (3, ...

BACKGROUND The reference intervals for hemoglobin A1c (Hb A1c) in pregnant women without diabetes are not well defined, and few examples of reference intervals established by networks of different laboratories are available. METHODS Five Italian Diabetic Care Units were involved in the study. Data were collected from 445 pregnant women without diabetes, selected on the basis of glucose challe...

OBJECTIVE Haemoglobin A1c (Hb A1c) is routinely used for monitoring glycemic control in patients with diabetes. Hb A1c seasonal fluctuations can be directly related to different biological, geographical and cultural influences. Our purpose was to evaluate seasonal variation of Hb A1c in a hospital-based adult population over a period of 5 years. MATERIALS AND METHODS We analyzed retrospective...

Complete automation of high-performance liquid chromatography (HPLC) for determination of hemoglobin F (%Hb F) and hemoglobin A1c (%Hb A1c) levels has made this procedure available in many clinical laboratories. However, the physiological changes in %Hb F during pregnancy and the effects of physiological and supraphysiological levels of %Hb A1c on measurement of %Hb F have not been studied exte...

The glycosylated hemoglobins A1a+b and A1c have been rapidly and precisely quantitated in 5-micro L samples of human blood hemolysate (approximately 240 micrograms of hemoglobin) by cation-exchange column chromatography. Total chromatographic is 22.0 min. Proportions of Hb A1c range from 3.85 to 6.71% in normal individuals and from 4.23 to 19.90% in diabetic subjects. Within-day variation was 1...

We evaluated three newly introduced systems for automated determinations of hemoglobin (Hb) A1c, which allow the processing of large amounts of samples in a routine clinical laboratory. We compared these methods--the Variant HPLC, the Hi-Auto A1c analyzer system, and the Roche immunoassay--with the Diamat HPLC system. All showed good precision and good concordance with the Diamat HPLC. The refe...

BACKGROUND Hemoglobin A1c (Hb A1c) measurement by hospital laboratory instruments, but not by point-of-care (POC) instruments, has been recommended for use to diagnose diabetes mellitus. We evaluated results from 13 Hb A1c external quality assurance (EQA) surveys over a 6-year period in Norway, from both POC instruments used in general practice (GP) offices and instruments in hospital laborator...

To the Editor: Glycohemoglobin assays are important for evaluating long-term glycemic control in patients with diabetes (1 ). Ion-exchange HPLC is commonly used for measuring hemoglobin A1c (Hb A1c), but hemoglobin variants (Hb) or increased fetal Hb concentrations may affect the quantification of Hb A1c by HPLC. The presence of Hb or high Hb F concentrations can be recognized by the separate e...